A shocking number of miserable camping trips trace back to the same root cause: someone checked a pleasant daytime forecast, packed accordingly, and got blindsided by an overnight low that never made it into their planning at all.
Clear skies — the exact condition that makes for a beautiful, sunny camping day — are also the condition that allows the most overnight heat loss from the ground (radiative cooling has nothing to trap it once the sun sets), meaning clear-sky nights are often colder than cloudy ones at the same elevation and season. A gorgeous, warm, cloudless afternoon can set up a genuinely cold, sometimes uncomfortably cold, overnight low — and a sleeping bag rated for the daytime high is not the same gear as one rated for the actual overnight number.
Same rule as hiking: roughly 3.5°F colder for every 1,000 feet of elevation gain. A campsite 3,000 feet above the nearest town’s forecast reading can run 10°F colder overnight than what a quick app check for “the area” suggested — check elevation-adjusted numbers, or at minimum mentally apply the lapse rate to whatever number you’re given.
A daily rain percentage isn’t enough for a multi-day trip — check the hourly breakdown for setup and breakdown windows specifically. Pitching or striking a tent in active rain is a genuinely different, more miserable task than doing it in a dry window, and a little hourly planning around a mostly-rainy day can still find a workable gap.
The daytime high tells you what to wear during the day. The overnight low tells you whether you’ll actually sleep. Camping planning needs both, and most people only check one.
Exposed, high-wind campsites need genuinely wind-rated tent gear — a budget tent that’s fine in calm conditions can fail structurally in sustained wind that a more exposed site (ridgelines, open meadows, coastal sites) is meaningfully more likely to experience than a sheltered, tree-covered site.
Check the overnight low, not just the daytime high, adjust for elevation using the lapse rate, look at hourly rain for setup/breakdown timing, and factor wind into tent choice for exposed sites. The daytime forecast is the part of the trip you’ll enjoy; the overnight forecast is the part that determines whether you actually sleep.